Pipe clamps are commonly used to join variously configured pipe ends in vehicle exhaust systems. One example is a pipe coupler which joins two pipe ends that are telescopically-connected such that the central axis of the smaller pipe end is coincident with that of the larger pipe end. The clamp can include a shoulder to accommodate the difference in pipe diameters to help achieve a strong clamping force on both the larger and smaller diameter pipe ends. See, for example, U.S. Pat. Nos. 4,261,600 and 4,312,526 to Cassel. Another example is a pipe clamp of the type used for a ball and flare joint in which a flared end partially overlaps a balled end when the two pipe ends are mated. This type of joint is referred to herein as a ball joint and it allows a certain amount of swivel of the balled end relative to the flared end before tightening the pipe clamp. Once clamped, the ball joint provides a fluid-tight connection between pipe ends even though a certain amount of angular misalignment of the pipe ends may exist. As used herein, angular misalignment means that that the axial centerlines of the two pipe ends are angled relative to each other and thus not coincident. A typical ball joint suitable for automotive exhaust system applications can, for example, be designed to accommodate up to about five degrees of angular misalignment of the pipe axes.
U.S. Patent Application Publication No. 2005/0029813 A1 discloses a ball joint and associated barrel shaped clamp. The balled insertion end section of one pipe includes two different spherical zones, with the second zone being located at the terminal end of the pipe and having a smaller outer radius that accommodates the wall thickness of the receiving end section of the other pipe. This allows the respective outer radii R1 and R3 of the first zone and receiving end section to be the same, such that together they substantially match the inner surface conformation of the barrel shaped clamp. This configuration uses a multiple-radius partially spherical conformation of the pipe end.